Pilot's Guide to Avionics 2012-2013 - 50

PILOT’S GUIDE

The looming ADS-B deadline and different standards have confused many pilots. But, it’s really simple: You can get all the technology’s benefits, now, with 978 UAT.

In Through The Out Door
Displaying ADS-B Data on Your Panel
S T O R Y B Y J O S E P H E . ( J E B ) B U R N S I D E

ew Year’s Day, 2020, is coming. That’s the day automatic dependent surveillance-broadcast will be required in some U.S. airspace, much the same as a Mode C transponder is needed now. On and after that day, pilots and aircraft owners will need ADS-B to operate in Class A airspace, at or above flight level 180. You will need it to access Class B and C airspace, plus operate at or above 10,000 feet mean sea level in most areas of the country while in Class E airspace. These requirements are fairly straightforward, and the deadline is unlikely to change. The good news: ADS-B is available today, right now. The Federal Aviation Administration has completed installing ground-based stations around the periphery of the U.S. and – except for gaps around the Great Lakes and the Upper Plains – it should be available at least above 1,000 feet MSL in those areas. In some areas – near a ground-based transmitter or a repeater – ADS-B is or will be available on the surface. The remainder of the U.S. will see its ADS-B coverage expanded and lowered as additional ground-based stations come online. That’s expected to occur by the end of 2013. If you are planning to buy a new or used aircraft between now and 2020, and fly it in the affected airspace, it makes sense to buy one already equipped with ADS-B. If you are happy with your current aircraft and plan to retain it into the next decade – and expect to fly in the affected airspace routinely – you need to be planning an avionics upgrade, if you want to retain your present utility. At a minimum, you need to equip for compliance with the ADS-B Out standard compatible with your normal operating altitude and destinations.

What’s Your Frequency? Why are your normal operating altitude and destinations important? It’s because the FAA is allowing two different types of ADS-B Out standards, using different radio frequencies. If your aircraft cruises in the flight levels, you must comply with the 1090 MHz extended squitter standard (1090ES), which will be required in Class A airspace and likely can be added to an existing Mode S transponder. Even if you never plan to take your Cherokee to the flight levels, 1090ES equipment will be adequate and usable at lower altitudes. For aircraft remaining below 18,000 feet MSL, equipment complying with the 978 MHz universal access transmitter (UAT) standard is allowed. Why is the FAA allowing two different equipment standards? Perhaps the primary reason involves frequency congestion: The 1090 MHz spectrum already is used for Mode A/C/S transponders and TCAS equipment, but it’s getting crowded, especially in terminal airspace. The expected proliferation of additional transmitters using that frequency once ADS-B requirements go into effect led the FAA to approve equipment using the 978 UAT standard outside Class A airspace. Although it’s too early to know for certain, the 978 UAT standard likely won’t be implemented on a widespread basis outside U.S. airspace. But, so far, we’ve been detailing the ADS-B Out standard as implemented by the FAA. This is the technology required to provide your position, speed, altitude and other data to FAA ground stations, and is only half of the ADS-B standard. The other half is ADS-B In, which allows your aircraft to receive and display ADS-B data via the flight information system-broadcast (FIS-B)

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Pilot's Guide to Avionics 2012-2013

Table of Contents for the Digital Edition of Pilot's Guide to Avionics 2012-2013